As can be seen in Table 1, a linear response in a wide COD range (from 106 to 1292 mg L−1 O) was obtained with all the
nanocomposite-derived sensors and the analytical performance in standard solutions make them amenable for the analysis of COD. Among them, the NiCu-based sensor showed the highest sensitivity and the lowest limit of detection (LOD). In contrast, the Ni-based sensor presented the poorest repeatability, with the calibration plot showing higher error bars and thereby resulting in the highest LOD. The analytical parameters of those previously reported COD sensors, that made use of catalysts of the same nature, are included in Table S1 in the Supporting Information, for comparative purposes.